Entick v. Carrington, a landmark piece of English
case law, dates from 1765 and provides dicta from Lord Camden that underpins, either directly or indirectly, all legislation relating to the police's powers of entry, search, and seizure, and in spirit, most of the current law on civil liberties.
The facts of the case were, that on November 11, 1762, the defendant, Nathan Carrington, "with force and arms" and a goon squad, broke into the property of the claimant, John Entick, claiming they had a warrant to search for "seditious papers." The judgement of Lord Camden, presiding, was that the person who provided the warrant had no authority to do that, and so Carrington was liable for trespassing.
The immediate and most notable consequences of the decision were that the executive branch of government, and their agents were limited in what they could do - specifically, it validated one of the branches of A. V. Dicey's theory on the rule of law, that the citizenry are free to do anything that is not specifically prohibited under law, but governmental agents are prohibited from doing anything that is not specifically allowed by case law or statute. The longer term consequences, however, are most notable in the case law surrounding the power of the police to search property. Lord Camden, in Entick v. Carrington said:
"By the law of England, every invasion of private property, be it ever so minute, is a trespass. No man can set foot upon my property without my licence, but he is liable to an action though the damage be nothing."
It was this dicta which meant that, unless you let them in voluntarily, the police cannot enter your property without a search warrant, reasonable grounds for suspecting you have stolen goods in that property, an arrest warrant, or they are in the process of making a lawful arrest or recapture of persons unlawfully at large, which are exceptions made by the Police and Criminal Evidence Act (1984).
Other cases of interest on this topic include:
Wershof v. Metropolitan Police Commissioner
Davis v. Lisle
Dimmock v. Hallett
McLorie v. Oxford
Jackson v. Stevenson
Jeffrey v. Black
Constitutional and Administrative Law, A. W. Bradley and K. D. Ewing
Howell's Law Report on the case, at http://www.constitution.org/trials/entick/entick_v_carrington.htm